I've been looking for a TH350 "K" case (also called a HD case) to build a doubler behind (due to general shortage of TH400 203s). I'm not real happy about loosing the strength of my TH400, so I figure if I'm going TH350, I want the HD/"K" case.

Problem is, it seems maybe I don't know how to ID the TH350 "K" case. I think K30guy or someone posted this a long time ago, but I can't find it now.

I *thought* it had these characteristics.
<ul type="square">
[*]A visibly thicker and reinforced case. Hard to ID this without something to compare to beside it...
[*]A "K" cast into the top of the main barrel of the case, behind the bell housing.
[*]A 6 bolt cast inspection cover under the torque converter, rather than the 4 bolt stamped sheet metal version.
[/list]

So, am I confusing this with the TH400, or completely clueless. Can someone please give me a clue?

The big 'fawkin' "K" is cast into the bell housing part on the TH350. If it doesn't have the "K" the other features won't be there either...so the "K" is what to look for (plus it makes sorting through the pile faster...)

[ QUOTE ]
The big 'fawkin' "K" is cast into the bell housing part on the TH350. If it doesn't have the "K" the other features won't be there either...so the "K" is what to look for (plus it makes sorting through the pile faster...)

Rene

[/ QUOTE ]

Rene, i hate to say this but ethier you are wrong or i am flat out BLIND. i was looking at my Th350 lastnight for russ. i cant not find a K anywhere on the case. BUT i do have 6 bolt holes. and the case is nice and thinck. thicker than i remember on a friends Th350.
grant

I know this is true for TH400's so I would assume it applies to TH350's as well...

The HD cases can come with the thin cover BUT will have the undrilled bosses cast on the housing that would accept the thick cover. All you would need to do is drill the case and you can bolt the bigger cover on.

Yep, old thread, but I am looking at transmissions and I didn't know about the "K" until I read this thread. Looks like I may have to have mine rebuilt since none of the ones I have looked at have a "K" or "HD"....

Take pics of the seating area where the dust cover sits. Show the thickness of the lips and the bolt holes, too.

Click to expand...

I would, but that picture isn't of my transmission

I have't dropped mine yet.

I don't know if I have a "K" on mine yet...and I haven't counted the dust cover holes yet. I am hoping that I do...but it's real hard to see that part of the bell housing with the transmission still in.

Personally,I dont think that having a "K" case is a MUST...it's "desireable" but not something you HAVE to have either..my K2500 has a TH400 that came from a car or 2wd truck and doesn't have the cast cover or even tapped holes in the case for one,yet I have managed to plow with it for 7 years without issues,and the truck gets the crap kicked out of it every time I use it too--not my choice,ots the type of wet cement snow we get here..if the "regular" cases are so "weak",why are so many still in use today that have had no issues?...heavy duty IS nice,but not something many of us will ever need,really...in a way I feel its more for bragging rights than actual nesessity ,why most 4x4 enthusiasts want the "best"....

Chief Brody, I doubt you would have a "K" case. It seems like an afterthought because a 73 I parted out, my 74, a spare th350/np203 which came from a 74, all came with non "K" cases.
What I'm trying to say is, the "K" case came out during the mid to late seventies. Around the same time when GM went from the frame support to the support braces. The braces that run from transfer case to bellhousing, and the two braces that run from torque converter cover to the motor mounts.

Mine is a K case. Factory tranny. Has a super thick aluminum inspection cover. Support rod for that pale the the motor mounts, support rod from tranny to transfer. Super thick bellhousing. Everything that has been mentioned, and it's a 79.

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